Titan's main feature is it's atmosphere. This natural color image shows the upper atmosphere and it's changing layers. It is an active place where methane molecules are being broken apart by solar ultraviolet light and the byproducts combine to form compounds like ethane and acetylene.

Lower down in the atmosphere, the haze turns into a smog of complex organic molecules. The thick, orange-colored haze absorbs visible sunlight, allowing about 10 percent of the light to reach the surface. The thick haze is also inefficient at holding in and re-radiating infrared (heat) energy back down to the surface. So, even though Titan has a thicker atmosphere than Earth, the thick global haze creates a weaker greenhouse effect than it is on Earth.